[PATCH v1] wifi: mac80211: fix swapped fq_overlimit/fq_overmemory in aqm debugfs

[PATCH v1] wifi: mac80211: fix swapped fq_overlimit/fq_overmemory in aqm debugfs

[Julius Bairaktaris]

The aqm file prints fq_overlimit with fq->overmemory and fq_overmemory
with fq->overlimit. The fq_overmemory line was added to the format string
after fq_overlimit while its argument went in before it, and the two have
been crossed since.

The counters are not interchangeable: fq_tin_enqueue() bumps fq->overlimit
for every packet the eviction loop drops, and fq->overmemory only for the
subset dropped because the memory limit was exceeded, so overmemory is
always the smaller of the two. Reading the file to tell which limit is
binding gives the opposite answer.

Fixes: 2a4e675d887b ("mac80211: Export fq memory limit information in debugfs")
Assisted-by: Claude:claude-opus-5
Signed-off-by: Julius Bairaktaris <julius@bairaktaris.de>
---
 net/mac80211/debugfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c
index a4d5461f6480..014f3c872706 100644
--- a/net/mac80211/debugfs.c
+++ b/net/mac80211/debugfs.c
@@ -96,8 +96,8 @@ static ssize_t aqm_read(struct file *file,
 			"RW fq_quantum %u\n",
 			fq->flows_cnt,
 			fq->backlog,
-			fq->overmemory,
 			fq->overlimit,
+			fq->overmemory,
 			fq->collisions,
 			fq->memory_usage,
 			fq->memory_limit,
-- 
2.53.0

Re: [PATCH v1] wifi: mac80211: fix swapped fq_overlimit/fq_overmemory in aqm debugfs

[Toke Høiland-Jørgensen]

Julius Bairaktaris <julius@bairaktaris.de> writes:

> The aqm file prints fq_overlimit with fq->overmemory and fq_overmemory
> with fq->overlimit. The fq_overmemory line was added to the format string
> after fq_overlimit while its argument went in before it, and the two have
> been crossed since.
>
> The counters are not interchangeable: fq_tin_enqueue() bumps fq->overlimit
> for every packet the eviction loop drops, and fq->overmemory only for the
> subset dropped because the memory limit was exceeded, so overmemory is
> always the smaller of the two. Reading the file to tell which limit is
> binding gives the opposite answer.
>
> Fixes: 2a4e675d887b ("mac80211: Export fq memory limit information in debugfs")
> Assisted-by: Claude:claude-opus-5
> Signed-off-by: Julius Bairaktaris <julius@bairaktaris.de>

Reviewed-by: Toke Høiland-Jørgensen <toke@toke.dk>

Re: [PATCH v1] wifi: mac80211: fix swapped fq_overlimit/fq_overmemory in aqm debugfs

[Johannes Berg]

On Sun, 2026-08-23 at 21:57 +0200, Julius Bairaktaris wrote:
> The aqm file prints fq_overlimit with fq->overmemory and fq_overmemory
> with fq->overlimit. The fq_overmemory line was added to the format string
> after fq_overlimit while its argument went in before it, and the two have
> been crossed since.
> 
> The counters are not interchangeable: fq_tin_enqueue() bumps fq->overlimit
> for every packet the eviction loop drops, and fq->overmemory only for the
> subset dropped because the memory limit was exceeded, so overmemory is
> always the smaller of the two. Reading the file to tell which limit is
> binding gives the opposite answer.

That's just LLM fluff, please rewrite the commit message manually to not
just like that.

johannes